In the food service industry, there is a need for refrigerated food storage in which different food items are readily available for preparation of foods such as sandwiches and pizza. In the "fast food" industry it has become a common practice to utilize preparation tables, which make the foodstuffs conveniently available to preparation personnel while maintaining the foodstuffs properly refrigerated.
Preparation tables, such as those used in fast food service, are typically constructed as a table in an arrangement, which provides refrigerated food storage and a work surface for food preparation. In a typical arrangement, the preparation table is provided with refrigerator cabinets under the table top for overnight food storage, a flat working surface at the front of the table top and a so-called "rail" which is part of the work area near the back of the table. The rail is an open-top refrigerated compartment usually extending the width of the table, with the open-top elevated several inches above the flat work surface at the front. The rail arrangement is used for ergonomic reasons and the refrigerated compartment thereof is provided with a plurality of open top food pans that are disposed side-by-side across the width of the rail. With the open top food pans supported near the upper surface of the rail, the food is easily reachable by the food preparation person standing at the front of the table. The refrigerated compartment in the rail is typically known as a "cold wall" pan or tank comprising a sheet metal open top pan or tank with refrigerant tubing bonded to the exterior surface of the pan liner. The tank constitutes the side walls and bottom wall of a refrigerated compartment and the food pans are supported therein by a rim or flange on the front and back of the pans which rest on ledge, or rails, inside the tank.
One of the difficulties with this arrangement is that the food in the upper portion of the open food pans is subjected to the ambient room temperature, which may be high enough to cause degradation of the food quality. With the food pans supported so that they extend downwardly into the refrigerated compartment, the food in the bottom of the pans is adequately refrigerated, but the food in the top of the pans may not be. Several possible solutions to this problem have been suggested. One is to lower the temperature of the cold wall tank. However, in the case of a high ambient temperature, when the temperature of the air below the pans is reduced adequately to maintain the food in the upper portion of the pans sufficiently cooled, freezing of food in the lower portion is likely to occur. It is desirable, in general, for proper food preservation to maintain the food at a temperature no higher than 40.degree. F., but higher than the freezing temperature.
Recently the National Sanitation Foundation (NSF) has promulgated a standard that requires all the food in the pans to be maintained at a temperature in the range of 33.degree. F. to 41.degree. F. Some food preparation tables have been promoted as meeting this standard. However, prior art food preparation tables have a number of drawbacks.
For example, the food preparation table disclosed in U.S. Pat. No. 5,363,672 has additional heat sink walls built on top of the typical cold wall pan, which are designed to provide an upper cooling zone above the product pans. One problem with this design is that the food preparation worker has to reach deeper to pick up food items in the pan. Worse yet, the heat sink walls are cold enough that moisture in the air can condense on them and run down into the product pans.
Other food preparation table designs have relied on a curtain of cold air being blown across the top of the food pans. U.S. Pat. Nos. 5,168,719 and 5,282,367 disclose food preparation tables with such a design feature. One drawback to this design is that the air that blows across the tops of the pans tends to dry out the food stored in the pans. Also, there is a high level of cold air lost to the room and warm air infiltration into the system.
Another food preparation table design is disclosed in U.S. Pat. No. 5,355,687. This design utilizes a plurality of cooling elements running perpendicular to the length of the tank. In this way each food product pan is surrounded on all sides by either the cold wall of the tank or an auxiliary cooling element. One of the problems encountered with this design is that the cooling area is thus divided up into "pigeon holes," and only product pans of the same dimension as the "pigeon holes" can be used. That is, a particular user cannot decide to interchange wider pans than those designed into the table. Since each food preparation table may be put to different uses, where different amounts of one product or another are preferably stored in an accessible location, and wherein the pan dimensions most desirable for use may change over the life of the food preparation table, if not quite frequently, this lack of flexibility is a distinct disadvantage, compared to most food preparation tables, where any combination of pan sizes can be utilized so long as they all fit within the length of the rail. Further, the amount of pan space is reduced by the space taken up by the auxiliary cooling elements.
Other designs have removed the bottom of the tank so that the cold air in the storage cabinets comes into contact with the bottom of the pans. One drawback to this design is that anything that spills or condenses in the tank can fall down into and contaminate food stored in the lower cabinets.
Another problem that has to be dealt with is that the food preparation table should be able to accommodate pans of the different standard depths, such as 4-inch and 6-inch deep pans. When 6-inch deep pans are to be used, there is very little room between the bottom of the pans and the conventionally designed cold wall tanks. If the tank were made taller, it would be more difficult to reach up into the pans to remove the food, and may not fit into the space available, which was designed for an earlier, shorter model food preparation table. Alternatively, if the tank were made deeper, it would encroach into the storage compartment space.
Thus, there is a need for a food preparation table that can meet the NSF standard without the drawbacks noted above. In particular, it would be advantageous if a food preparation table could be constructed with little modification to conventional designs so that existing manufacturing fixtures and designs can be utilized as much as possible, and the resulting food preparation table will fit within the space designed for prior tables.